Perceptual narrowing continues throughout childhood: Evidence from specialization of face processing.

Face recognition shows a long trajectory of development and is known to be closely associated with the development of social skills. However, it is still debated whether this long trajectory is perceptually based and what the role is of experience-based refinements of face representations throughout development. We examined the effects of short and long-term experienced stimulus history on face processing, using regression biases of face representations towards the experienced mean. Children and adults performed same-different judgments in a serial discrimination task where two consecutive faces were drawn from a distribution of morphed faces. The results show that face recognition continues to improve after 9 years of age, with more pronounced improvements for own-race faces. This increased narrowing with age is also indicated by similar use of stimulus statistics for own-race and other-race faces in children, contrary to the different use of the overall stimulus history for these two face types in adults. Increased face proficiency in adulthood renders the perceptual system less tuned to other-race face statistics. Altogether, the results demonstrate associations between levels of specialization and the extent to which perceptual representations become narrowly tuned with age.

Refinement of face representations by exposure reveals different time scales of biases in face processing.

Experience modulates face processing abilities so that face discrimination and recognition improve with development, especially for more frequently experienced faces (e.g., own-race faces). Although advanced models describe how experience generally modulates perception, the mechanism by which exposure refines internal perceptual representations of faces is unknown. To address this issue, we investigated the effect of short- and long-term experienced stimulus history on face processing. Participants performed same-different judgments in a serial discrimination task where two consecutive faces were drawn from a distribution of morphed faces. Use of stimulus statistics was measured by testing the gravitation of face representations towards the mean of a range of morphed faces around which they were sampled (regression-to-the-mean). The results demonstrated regression of face representations towards the experienced mean and the retention of stimulus statistics over days. In trials where regression facilitated discrimination, the bias diminished the otherwise disadvantage of other-race over own-races faces. The dynamics of the perceptual bias, probed by trial-by-trial performance, further indicated different timescales of the bias, depending on perceptual expertise: people with weak face-recognition skills showed the use of a stable reference, built on long-term statistics accumulated over many trials, along with an updating of this reference by recent trials. In contrast, the strong face recognizers showed a different pattern where sequential effects mostly contributed to discrimination, with relatively minimal reliance on the long-term average for other-race faces. The findings suggest a mechanism by which exposure refines face representations and reveal, for the first time in adults, associations between levels of specialization of perceptual representations and the extent to which these representations become narrowly tuned.

The safety of preoperative sedation in children with sleep-disordered breathing.

OBJECTIVE: To prospectively monitor children who received preoperative sedation with midazolam hydrochloride prior to adenotonsillectomy (T&A) for treatment of sleep-disordered breathing with continuous pulse-oximetry to detect potential respiratory compromise. DESIGN: Prospective, observational study. SETTING: Hospital-based pediatric otolaryngology practice. PATIENTS: Seventy children, aged 1-12 years, diagnosed with sleep-disordered breathing by clinical evaluation or polysomnography (PSG), with a median RDI of 14.25, undergoing T&A. METHODS: Children underwent a standardized anesthesia protocol including preoperative oral midazolam hydrochloride 0.5mg/kg, standard American Society of Anesthesiologists (ASA) monitoring, mask induction with sevoflurane, muscle relaxant with reversal if indicated, and intravenous dexamethasone sodium phosphate 0.5mg/kg. Children were monitored in the hospital until discharge criteria were met. Selected children with severe OSA were monitored overnight on the pediatric floor or the pediatric intensive care unit. Adverse respiratory events were defined as upper airway obstruction, hypoventilation, desaturation, bradycardia, or sustained lethargy. MAIN OUTCOME MEASURES: Incidence of pre and postoperative obstructive complications. RESULTS: During the study period only two patients (2.9%) had a measurable adverse event directly related to the administration of the sedation. CONCLUSION: Based on sporadic reports of adverse airway events in children with obstructive sleep apnea receiving sedation, these children frequently do not receive preoperative sedation. Given the low morbidity of preoperative sedation in our population, many children with sleep-disordered breathing may safely be pre-medicated.

Levels of evidence in otolaryngology journals.

OBJECTIVE: To identify trends in clinical research and levels of evidence in otolaryngology journals. STUDY DESIGN AND SETTING: We reviewed all original research articles from 1993, 1998, and 2003, in 4 major otolaryngology journals. Levels of evidence were graded 1 (strongest) through 5 (weakest). RESULTS: Of 2584 total articles, 1924 (75%) were clinical research. During the study period, there was increased median sample size (from 22 to 30, P=0.06), more planned research (from 30% to 37%, P=0.023), more internal control groups (from 36% to 43%, P=0.011), and more articles with P values (from 26% to 45%, P<0.001) or confidence intervals (from 1.2% to 7.6%, P<0.001). Most evidence was level 4 (57%), but median levels increased slightly over time (P=0.027). Therapy articles had the weakest evidence (80% levels 3 to 5) and diagnostic test assessments had the strongest (75% levels 1 and 2). CONCLUSION: Although clinical research increased in quantity and quality, sample sizes were modest, most articles lacked controls, and confidence intervals were rare. Therapy articles would benefit from higher evidence levels. SIGNIFICANCE: By defining the current levels of evidence in otolaryngology journals, this overview should help guide future efforts.